[2.1.5] Updated composer repository to 2.1.5 packages
[2.1.5] dist and pyrus packages
Release epub and pdf, too!
Added Zend_Test to pyrus-package-filter.php script
Zend_Test 2.1.5 pyrus packages
Corrected links for stable package

- Will need to make sure that composer's "dev" packages are not selected in the
  future.